The interfacial sliding of the composite steel-concrete structures is unavoidable due to the debonding between the steel and concrete of the composite steel-concrete structures is less than that of the reinforcement concrete. The relative sliding of the interface is primarily yielded by the insufficient shear bond strength at the interface of the steel and concrete, which reduces the composite function and leads to the inconsistent deformation. The mechanical and electrical instruments were usually applied for measurement of the sliding in the prior art; however, those instruments have high requirements on the application environment; for instance, the environments with high temperature, low temperature or strong electromagnetic interference are not suitable for application. Moreover, the sliding between concrete and steel is usually rather small. Therefore, a kind of measuring device with high precision is needed.